Ion detection apparatus

Abstract

Ion detection apparatus has an ionizer provided with an ionizer volume for receiving a specimen to be analyzed. An electron gun is operatively associated with the ionizer for bombarding the specimen with an electron beam and converting the specimen into ions. An analyzer receives the ions from the ionizer volume and includes a detector for detecting the ions. The electron gun has focusing means for varying the size and intensity of the electron beam. The electron gun may have an accelerating anode, a focusing collimator and a second anode. The ionizer means may have an extractor lens and collimating lens as well as a groundplate. The ionizer means may have an electron collecting plate for receiving electrons which pass through the ionizer volume and providing feedback regarding the electron beam.

I claim: 
     
       1. Ion detection apparatus comprising, ionizer means having an ionizer volume for receiving a specimen to be analyzed,   electron gun means operatively associated with said ionizer means for bombarding said specimen with an electron beam and converting at least portions of said specimen into ions, said electron gun means having a filament and an extraction plate, said extraction plate being disposed on the ionizer means side of said filament,   analyzer means for receiving said ions from said ionizer volume, said analyzer means having detector means for detecting the presence of said ions; and   said electron gun means also having focusing means for varying the size of said electron beam, said focusing means having means for varying the spacing between said filament and said extraction plate.   
     
     
       2. The ion detection apparatus of claim 1 wherein, said extraction plate disposed in spaced relationship with respect to said filament, and   said electron gun means having an accelerator anode disposed in spaced relationship with respect to said extraction plate.   
     
     
       3. The ion detection apparatus of claim 2 including, said electron gun means having a second anode operatively associated with said ionizer means.   
     
     
       4. The ion detection apparatus of claim 3 including, said electron guns means having a focusing collimator interposed between said accelerating anode and said second anode for assisting with focusing said electron beam.   
     
     
       5. The ion detection apparatus of claim 1 including, said focusing means having an adjustment member which when rotated will effect relative translational movement between said filament and said extraction plate.   
     
     
       6. The ion detection apparatus of claim 1 including, said ionizer means having an electron collection plate for receiving portions of said electron beam passing through said ionizer volume, and   feedback current means for providing information regarding said electron beam.   
     
     
       7. The ion detection apparatus of claim 1 including, said ion detection apparatus having a vacuum chamber, and   vacuum pump means operatively associated with said chamber for establishing at least a partial vacuum therein.   
     
     
       8. The ion detection apparatus of claim 7 including electron gun means having disconnect means for separating said focusing means from said ion detector from the remainder of said ion detector apparatus.   
     
     
       9. The ion detection apparatus of claim 8 including, said ionizer means having disconnect means for separating said ionizer means from the rest of said ion detector apparatus.   
     
     
       10. Electron gun apparatus for use with ion detection means comprising, a filament,   an extraction plate, and   focusing means for establishing relative movement between said filament and said extraction plate.   
     
     
       11. Electron gun apparatus of claim 10 including, said focusing means having rotatable means which establish relative translational movement of said filament with respect to said extraction plate.   
     
     
       12. Electron gun apparatus of claim 11 including, said electron gun means having an accelerating anode and a second anode.   
     
     
       13. Electron gun apparatus of claim 12 including, focusing collimator means interposed between said accelerating anode and said second anode.